This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Vaccination is the most cost-effective medical and public health intervention known to prevent death and disease worldwide. Vaccines have been instrumental in increasing life expectancy and reducing the burden of childhood diseases like mumps, polio, measles, rubella, diphtheria, tetanus and pertussis. However, the mechanisms that mediate the efficacy of these vaccines remain unclear. Indeed, in general, immune responses to vaccination in infants are poorly understood and have not been well studied with modern immunological tools. Moreover, most vaccine efficacy studies have focused on protective antibody responses and much less is known about cell-mediated immunity and antigen-specific T cell responses following immunization. Understanding the immunological basis of successful vaccines would provide important insights for designing new vaccines for complex infectious diseases like tuberculosis. The primary goal of this study is to examine neonatal T cell responses induced by acellular pertussis vaccination during the first year of life. This study represents a close collaboration between Dr. Rana Chakraborty at the Department of Pediatrics and the Ponce Center and Dr. Rengarajan at the Division of Infectious Disease and the Emory Vaccine Center and takes advantage of existing clinical and basic science expertise and infrastructure within the two groups. Data generated through these exploratory studies will lay the foundation for future detailed studies on vaccine-induced immunity in neonates.